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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 7402. |
Benny's mother was finding it difficult to cook food in the kitchen there was no light in the kitchen due to a power cut. She complained about this to Benny. Benny took a big plane mirror from the house and made it stand in sunshine (outside the house) in such a way that sun's rays falling on it were diverted into the kitchen. This arranagement provided sufficient light in the kitchen due to which Benny's mother could finish her work in the kitchen comfortably. (a) Which phenomenon of light is made use of by Benny in this case ? (b) Benny's mother could also cook rice and dal by using a device kept in sunshine outside the kitchen in which a plane mirror is used as a reflector. Name the device. (c) State four characteristics of images formed by a plane mirror. (d) What values (or qualities) are displayed by Benny in this episode ? |
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Answer» Solution :(a) Benny makes USE of the phenomenon of reflection of light from a PLANE mirror. (b) Solar cooker. (c) The image formed by a plane mirror is (i) virtual and erect (ii) same size as the OBJECT (iii) same DISTANCE behind the mirror as the object is in front of the mirror (iv) laterally inverted (or sideways reversed). (d) The values (or qualities) displayed by Benny in this episode are (i) Awereness (or knowledge) about the reflection of light (ii) Ability to apply knowledge in real LIFE situations, when needed, and (iii) Desire to help his mother. |
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| 7403. |
What is the role of the seminal vesicles and the prostate gland. |
| Answer» Solution :The secretion from SEMINAL VESICLES and prostate GLANDS lubricate the sperms and provide a fluid medium for easy TRANSPORT the secretions also provide nutrient in the from of FRUCTOSE calcium and some enzymes. | |
| 7404. |
An electric iron of resistance 20Omega takes a current of 5 A. Calculate the heat developed in 30 sec. |
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Answer» Solution :R = 20` Omega` I = 5 A t = 30 SEC `H = I^(2) RT = 5^(2) xx20 xx30 = 15000 J = 15 J` |
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| 7405. |
List four characteristics of the image formed by a convex lens of focal length 20 cm when the object is placed in front of it is a distance of 10 cm from its optical centre . |
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Answer» SOLUTION :Characteristics of image formed by the convex lens : (i) The image will be on the same side of the lens as the OBJECT ( as the object is between `F_(1) and ` O). (II)It will be enlarged . (iii) It will be virtual . (iv) It will be erect . |
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| 7406. |
Complete the chart as per the objectives of first aid. |
Answer» SOLUTION : 
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| 7407. |
Three infinitely charged sheets are kept parallel to xy plane having charge densities as shown in Fig. Then the value of electric field at P is |
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Answer» `(-4 SIGMA)/(in_(0) hat(k)` |
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| 7408. |
An electric motor takes 5 A from a 220 V line. Determine the power of the motorand the energy consumed in 2 h. |
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Answer» Solution :Here ,I = 5 A. V = 220 V, t = 2 H = (2` xx 60 xx` 60) s = 7200 s Power P = VI = 220 `xx` 5 = 1100W= 1100 J / s Now, Energy CONSUMED W = Pt = 1100 J / s `xx` 7200 s = 7920000J `= 7.92 xx 10^6 J` OR Energy consumed W = Pt = 1100W `xx` 2 h = 2200Wh `=2.2 xx 10^3 Wh` `= 2.2 kWh` |
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| 7409. |
Construct a terrestrial food chain comprising four trophic levels.(b) What will happen if we kill all the organisms in one trophic level ?(c) Calculate the amount of energy available to the organisms at the fourth trophic level if the energy available to the organisms at the second trophic level is 2000 J. |
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Answer» Solution :GROSS `RARR` Rabbit `rarr` Wolf `rarr` Tiger (b) If all organisms of any one trophic level are killed then its previous trophic level organisms will increase in number to such an extent that their previous trophic level will also become extinct and the next trophic level organisms will also get extinct. For e.g., if we remove all WOLVES then rabbits will increase and will eat up all the GRASS, at the same time tigers will also perish because of lack of their food. (c) Energy is transferred as per 10% law : Hence, if energy available at second trophic level is 2000 J then THIRD trophic level will have `(10)/(100)xx2000` = 200 J : and fourth trophic level will have `(10)/(100)xx200` = 20 J. |
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| 7410. |
Give one important advantage of AC over DC ? |
| Answer» Solution :AC can be stepped up and stepped down which means that the VOLTAGE can be INCREASED or decreased. Hence it can be transmitted to long DISTANCES WITHOUT much LOSS of energy. So AC is preferred over DC. | |
| 7411. |
Maximum effect of alcohol occurs on ------------system. |
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| 7412. |
How can solar energy be harnessed? Mention any two limitations in using solar energy. How are these limitations overcome ? |
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Answer» Solution :SOLAR energy can be harnessed directly by using a solar cooker, solar heater, or solar cells. In solar cooker the sun.s heat energy is used for cooking. In a solar heater, heat energy is used to heat the water. In solar cells, solar energy is converted into electricity. Limitations in using solar energy are : Solar energy is not available in night and when the sun is hidden under clouds The domestic use of solar cells for PRODUCTION of electricity is not possible due to high cost These limitations can be overcome by : FIRST limitation can be overcome by converting solar energy into electrical energy and storing it for future use Second limitation energy and storing it for future use Second limitation can be overcome by the Indian government TAKING certain steps to reduce PRICE of solar cells |
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| 7413. |
Explain partial reflection, critical angle and total internal reflection with the help of a neat labelled diagram. |
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Answer» Solution :i. When a ray of light enters a rarer medium from a denser medium, it gets partially reflected i.e., part of the light gets reflected and comes back into the denser medium obeying the laws of reflection. This is CALLED partial reflection. ii. The rest of the light gets refracted and goes into the rarer medium. As light is going from denser to rarer medium, it bends away from the normal i.e., the angle of incidence (i) is SMALLER than the angle ofrefraction (r). iii. According to Snell's law, the refractive index of the material is constant. Hence, on mcreasmg the angle of incidence the angle of REFRACTION (r) increases. iv. For a particular value of i for which, the value of r becomes equal to `90^(@)`, is called the critical angle. For i = critical angle `=i_(c), r=90^(@)` `""_(2)n_(1)=(sin i_(c))/(sin 90^(@))=sin i_(c) ..... (because sin 90^(@) = 1)` v. For angles of incidence larger than the critical angle, the angle of refraction is larger than `90^(@)`. Such RAYS return to the denser medium as shown in the figure. Thus, all the incident light gets reflected back into the denser medium. This is called total internal reflection.  Partial reflection, Critical angle and total internal reflection |
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| 7414. |
Define 1 dyne . |
| Answer» Solution :The amount of forcerequiredfor a body of MASS 1 gram producesan acceleration of ` 1 CMS^(-2) 1 " dyne "= 1 g cms^(-2), " ALSO " 1 N=10^(5) " dyne " ` . | |
| 7415. |
Derive the relation R=R_1+R_2+R_3. When resistors are joined in series. |
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Answer» Solution :In series combination, the same current FLOWS in all the resistances but the potential difference across each of the resistance is DIFFERENT. According to Ohm law , we have `V_1=IR_1,V_2=IR_2,V_3=IR_3` IF the total potential difference between A and B is V, then `V=V_1+V_2+V_3` `=IR_1+IR_2+IR_3=I(R_1+R_2+R_3)` LET the equivalent resistance be R, then V=IR and hence `IR=I(R_1+R_2+R_3)` `implies R=R_1+R_2+R_3` 
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| 7416. |
State different ways to induce current in a coil. |
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Answer» Solution :The current in a coil can induced by the FOLLOWING ways: (i) By rotating the coil in the magnetic FIELD between the poles of U-shaped MAGNET. (ii) By keeping the coil stationary and MOVING a magnet inside it. (iii) By changing the current continuously in an ANOTHER coil kept near it. |
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| 7417. |
Explain why, in a nuclear reactor, the chain reaction stops if the control rods are fully inserted into the graphite. |
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| 7418. |
The value of acceleration due to gravity (g) is not the same at all the points on the surface of the earth. |
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| 7419. |
Overloading can be avoided by connecting many appliances at a time in the circuit. |
| Answer» SOLUTION :False. REASON : Overloading can be avoided by not connecting MANY APPLIANCES at a time in the circuit | |
| 7420. |
.................. is the amount of heat required to raise the temperature of ............ Water through Ikelvin. |
| Answer» SOLUTION :ONE KILO CALORIE, one KG | |
| 7421. |
What are the environmental consequences of the increasing demand for energy? What steps would you suggest to reduce energy consumption? |
| Answer» Solution :INDUSTRIALIZATION increases energy demand. Fossil fuels are easily accessible energy sources that fuifil this demand. The increased use of fossil fuels has a harsh effect on the environment. Too much exploitation of fossil fuels increases the level of greenhouse gases in the atmosphere, resuting in global warming and a RISE in the sea level. It is not possible to completely reduce the consumption of fossil fuels. However, some measures can be taken such as using electrical appliances wisely and not wastingg electricity., avoiding unnecessary usage, and the like. Eficlency of energy sources should be MAINTAINED by getting them regularly serviced. These small steps may help in REDUCING the consumption of NATURAL resources and conserving them. | |
| 7422. |
The path along which light travels in a homogenous medium is called the |
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Answer» BEAM of LIGHT |
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| 7423. |
Why are traffic signals red in colour? |
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Answer» Solution :(i) Red light has the HIGHEST wavelength. (ii) It is scattered by atmospheric particles. (iii) So red light in able to TRAVEL the longest DISTANCE through fog , rain etc. |
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| 7424. |
Equipment such as water boiler, electric cooker, electric bulb make use of the .......... .. effect of electric current |
| Answer» SOLUTION :HEATING | |
| 7425. |
Mention the provision of two different cunent ratings in our domestic circuits. Explain with reason, the advantage of such a provision. |
| Answer» Solution :The TWO different current RATINGS provided in domestic circuits are 5A and 15A. This is because different ELECTRICAL appliances have different power ratings, so they draw different currents when connected in the mains. Some appliances need smaller currents, while some other need HEAVY currents. | |
| 7426. |
Which phenomenon is responsible for the twinkling of stars? |
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Answer» Atmosphere refletion |
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| 7427. |
Explain the rules for obtaining images formed by a convex lens with the help of ray diagram. |
Answer» Solution :Rule - 1 : When a ray of light strikes the convex or concave lens obliquelt at its optical centre it continues to FOLLOW its PATH without any DEVIATION Rule 2: When RAYS parallel to the PRINCIPAL axis strikes a convex or concave lens , the refracted rays are converged to (convex lens) or appear to diverge from (concave lens) the principal focus  Rule -3 : When a ray passing through (convex lens) or directed toward (concave lens) the principal focus strikes a convex or concave lens , the refracted ray will beparallel to theprincipal axis 
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| 7428. |
Draw a ray diagram to show the path of the reflected ray corresponding to an incident ray of light parallel to the principal axis of a convex mirror and show the angle of incidence and angle of relection on it. |
Answer» SOLUTION :
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| 7429. |
What is gauge pressure and how is a manometer used for measuring pressure differences? |
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Answer» Solution :Gauge pressure: The Pressure p, at depth below the surface of a liquid open to the atmosphere is greater than atmospheric pressure at an amount pgh. The excess pressure (P-Pa), at depth h is called as " gauge pressure at the point". Measurement of pressure difference using a Manometer: An open tube manometer is a useful instrument for MEASURING pressure differences. It CONSISTS of a U-tube containing a suitable liquid i.e., a low DENSITY liquid (such as oil) for measuring small pressure differences and high density liquid( such as mercury) for large pressure differences. One end of the tube is open to the atmosphere and other end is connected to the SYSTEM whose pressure to be measured.  The pressure P at A is equal to pressure at point B. If the pressure in the vessel is more than the earth's atmospheric pressure, then the level of liquid in arm -I of U-tube will go down upto point A and the level of liquid in arm-II of U-tube will rise up to point C. Then the pressure of air in vessel is equal to pressure at point A. Let 'h' be the difference of liquid levels in the two arms of U-tube. Let `rho` be the density of liquid in U-tube and Pa be the atmospheric pressure. Since , the pressure is same at all points at the same level, so pressure at point A, `P_A`= pressure at point B =presssure at C + pressure due to column of liquid ofheight 'h' So, `P_A=P_C+hrhog` or `P_A-P_C=h rho g`___(1) Here `P_C=Pa`= atmospheric pressure. If `P_A=P`, then from EQ........(1) P-Pa=` h rho g` Here,`P-Pa=P_g`=gauge pressure = `h rho g`. |
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| 7430. |
A thermodynamic system is taken from original state D to an intermediate state E by the linear process shown in figure. Its volume is then reduced to the original value from E to F an isobaric process. Calculate the total work done by the gas from D to E and E to F. |
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| 7431. |
Propulsion of rockets is based on the ……………………… and ……………………… |
| Answer» Solution :LAW of conservation of linear MOMENTUM & NEWTONS third law | |
| 7432. |
Statement 1 : The current produced in au AC generator is of alternating nature. Statement 2 : In AC generator, after every half rotation of the coil the current changes direction. Explain Statement 1 with the help of Statement 2. |
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Answer» Solution :1. In an AC generator, during the first HALF of the REVOLUTION of the armature coil, the current flows out through one of the brush in one direction. 2. During the SECOND half of revolution, the current flows out through another brush in the reverse direction and this process is repeated. |
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| 7433. |
Relation between acceleration due to gravity (g) and the universal gravitational constant (G) is ………………………….. |
| Answer» SOLUTION :`G=(G)/(R^(2))` | |
| 7434. |
Explain how the specific heat capacity of a solid can be determined (measured) by the method of mixture. |
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Answer» Solution :A hot solid is put in water in a calorimeter. The mixture is stirred continuously and the maximum TEMPERATURE of the mixture is measured with a thermometer. HEATEXCHANGE between the hoysolid, water and calorimeter RESULTS in all bodiesattainingthe sametemperature after some time. Hence, according to the principle of heat exchange, heat lost by the solid = heat gained by the water in the calorimeter + heat lost by the solid = heatgained by the water in the calorimeter + heat gained by the calorimeter. Now, heat lost by the solid (Q) = mass of the solid ` xx ` its specific heat CAPACITY ` xx` DECREASE in its temperature m heat gained by the water `(Q_(1))`= massof the water ` xx ` its specific heat capacity ` xx` increase in its temperature and heat gained by the calorimeter ` (Q_(2))`=mass of the calorimeter `xx` its specific heat capacity ` xx` increase in its temperature . Heat lost by the hot object= heat gained by the calorimeter + heat gained by the water . ` = Q_(2) + Q_(1)` Usingthis equation , the specific heat capacity of the solid can be determined (measured ) when the other quantities are known. |
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| 7435. |
Most of the disasters have occurred in the ............ . continent and ............. ocean. |
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| 7436. |
List two characteristics of a good source of energy. |
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Answer» SOLUTION :(i) Easily ACCESSIBLE and EASY to store. (II) Economical and eco-friendly. |
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| 7437. |
Statement 1 : In DC generator, the flow of current in the circuit is in the same direction. Statement 2: Split ring is used in a DC generator . Explain Statement 1with the help of Statement 2. |
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Answer» SOLUTION :1. In a DC generator, SPLIT ring is fixed on the axle. 2. Because of this arrangement, are BRUSH in the one brush in the circuit is always in contact with the arm of the armature moving up in the magnetic field. 3. The other brush is in contact with the arm of the armature moving downwards in the magnetic field. 4. Therefore, in DC generator, the FLOW of current in the circuit is in the same direction. |
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| 7438. |
(i) A person's image when seen through a stream of hot air arising above a fire disperse to waver. Explain. (ii) Define dispersion. How does a prism disperse white light? (iii) Which colour of light bends the most and the least? |
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Answer» Solution :(i) In the region above the fire, the hot air is lighter than the COOL air above it. Further the refractive index of hotter region is less than the cooler region and it is not static. These physical conditions are not steady. Subsequently the image when seen through the hot region is not STATIONARY. The apparent position of the object fluctuates. This gives the wavering effect to the image. (ii) The phenomenon of obtaining a spectrum of COLOURS by PASSING white light through the prism is known as dispersion. Dispersion occurs because the refraction of different colours travel with different speeds in a refracting medium. Speed of violet colour is LEAST and that of the red colour is the most. Hence the refractive index of the medium is largest for violet colour and least for the red colour. (iii) As a result, the refraction or bending of violet colour is the maximum and that of red colour is minimum This difference in the extent of bending of different colour of light causes dispersion of white light into its constituent colours as they emerge out of prism. Red colour bends the least and violet bends the most. |
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| 7439. |
A narrow beam of white light is shown to pass through a triangular glass prism. After passing through the prism, it produces a specturm XY on a screen. (a) State the colour seen at X and Y. (b) Why do different colours of white light bend through different angles with respect to the incident beam of light ? . |
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| 7440. |
The telescope called‘ChandraX— ray Observàtory' is placed in the outerspace. What is the advantage of placing it there? Explain with reference to the scattering of light in the atmosphere. |
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| 7441. |
Project: Enlist various factors affecting the social health in your residential area. Decide the necessary changes to correct the situation and implement those changes. |
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Answer» Solution :i. Some of the factors which affect the social health in my resisdential AREA are as follows : a. Good condition of roads. B. Availability of school, colleges, hospitals, medical centres as well as banks in close vicinity. c. Availability of shops selling daily required things and meicines. d. Social gatherings, meetings and siscussings on important social issue conducted in the area. e. Increase in traffic and hence pollution during morning and EVENING peak hours. F. Honking of vehicles on the nearest highway leading to sound pollution. ii. The changes which can be implemented of correct issue highlighted in points (e) and (f) are as follows: a. Diversion of traffic during peak hours away from residential areas. b. installing sound absorbing devices to control the sound to safe decibel levels. |
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| 7442. |
The spectral lines having frequency equal to the incident ray frequency is called _________ . |
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Answer» SPECTRAL lines |
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| 7443. |
Nuclear fission is a thermonuclear reaction. |
| Answer» SOLUTION :NUCLEAR FUSION is a THERMONUCLEAR REACTION. | |
| 7444. |
The dimensional formula for thermal resistance is |
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Answer» `[ML^2T^(-3) K^(-1)]` |
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| 7446. |
Does the AC generator have any slip ring? |
| Answer» Solution :The AC GENERATOR has TWO slip RINGS. | |
| 7447. |
Try this Material: Convex lens, screen, metre scale, stand for the lens etc. Method: Keeping the screen fixed, obtain a clear image of a distant object like a tree or a building with the help of the lens on the screen. Measure the distance between the screen and the lens with the help of the metre scale. Now tum the other side of the lens towards the screen. Again obtain a clear image of the distant object on the screen by moving the lens forward or backward. Measure the distance between the screen and the lens again. What ls this distance between the lens and the screen called? |
| Answer» Solution :The focal length of a lens depends upon the radii of curvature `(R_(1), R_(2))` of the lens and the REFRACTIVE INDEX of the material of lens (e.g. GLASS) with respect to the SURROUNDING medium, i.e. , air. | |
| 7448. |
Try this Material: Convex lens, screen, metre scale, stand for the lens etc. Method: Keeping the screen fixed, obtain a clear image of a distant object like a tree or a building with the help of the lens on the screen. Measure the distance between the screen and the lens with the help of the metre scale. Now tum the other side of the lens towards the screen. Again obtain a clear image of the distant object on the screen by moving the lens forward or backward. Measure the distance between the screen and the lens again. What will happen if you use a concave lens in this experiment? |
| Answer» SOLUTION :If `""_(g)n_(a)` =1.5 and `R_(1)=R_(2)=R`, then f=R . If a CONCAVE lens is USED in the above EXPERIMENT , no image will be formed on the SCREEN. | |
| 7449. |
A current of 4 A flows through a 12 V car headlight bulb for 10 minutes. How much electrical energy is consumed during this time? |
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Answer» Solution :Given : Current (I)= 4A, Potential DIFFERENCE (V) = 12 V, TIME (t) = 10 minutes =10 x 60 = 600s To find:Electric energy consumed FORMULA:Electric energy consumed = work done = Vlt Solution :Electric Energy consumed = Vlt= 4 X 12 x 600=28800 J `therefore` Electric energy consumed is 28800 J |
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